PINNED - Lithium battery conversion/info

[cdb0ewm]

I am putting together a 24v Headway setup using 8 packs of 8 cells each. If I understand the wiring diagram above showing the balancing wiring configuration, will I be basically duplicating it, one for each set of 12volts. Since the Hyperion charger has 2 plugs/harnesses for balancing, for the second 12volt set should I use the second plug on the Hyperion charger or do I do it all with one plug.

Thanks

[CPguy]

@ cdb0ewm: If you count the wires you will see that each "plug" as you call it just has wires for max. 7 cells in series (7s). So if you want 8 cells in series (8s) you will have to use both balancer outlets of the Hyperion in some way. You are free to choose a configuration. e.g. 7:1, 6:2, 5:3 or 4:4.

Of course, the other side of the balancer cable can just be one plug (making it a "Y" form cable).

[Burgerman]

You can use connections 1 to 8 (7 cells) on plug A.
And connection 1 to 2 for the 8th cell.

Or you can use connections 1 to 5 on both A and B as separate "12v" battery connections.

In both cases, pin 8 on the A connector, and pin 1 on the B connector will go to the same place on the battery.

[long gone]

Headway Lithium pack could well be a means of making an Alber Adventure work for me as the normal power packs are easy to change because they have to be changed often with "real world" use. This is still only at the ideas stage with a near standard , well almost, Quikie F55s as the ongoing project for modifying the motive power source.

[Burgerman]

Apart from its size, the biggest problem with that Alber Adventure chair is its bespoke tyres and its stupidly small overworked batteries. Lithium conversion using hi rate headway cells would be a huge improvement. And likely you would no longer need to swap them.

[long gone]

The tyre problem has me considering tyres from a monkey bike found with some searching of the net and foam filling them for puncture proofing. With power packs having something in reserve appeals when going off the beaten track, get there or bust, brings in Murphys law if it can go wrong it will and a switch able reserve for such events is somewhere in my thoughts when drawing up a usable alternative for the manufacturers offering.
Brushless motors and epicyclic gearing along with the nearest thing I have seen to suspension on a powerchair make the power systems shortcomings worth some investigation and the Headway packs are topping my list for solutions. I have a Honda !kw suitcase generator though the idea of travelling with a molotov cocktail attached is a less than ideal back up for running out of charged cells.

[Burgerman]

I thought they were an oddball size. Meaning replacing wheels with standard inch diameter/width versions.

[ex-Gooserider]

I am putting together a 24v Headway setup using 8 packs of 8 cells each. If I understand the wiring diagram above showing the balancing wiring configuration, will I be basically duplicating it, one for each set of 12volts. Since the Hyperion charger has 2 plugs/harnesses for balancing, for the second 12volt set should I use the second plug on the Hyperion charger or do I do it all with one plug.

Thanks

Unless you have a definite reason to need multiple separate packs, you are MUCH better off to build the pack as one block using serial and parallel connections (typically tie all the batteries in each paralell string together w/ bars, then use one or two bars to tie those strings together in series.... This is what you will end up with electrically anyway, and it's a lot better if you can do it mechanically as well...

That way you don't need to do wiring between the strings, only need one balancing harness for the entire pack, and end up with a cleaner system...

If you do have to do multiple packs, for instance if you are having to fit into separate battery boxes, I'd do as few packs as possible, with each pack consisting of several 8-cell parallel strings so that you only need to run one set of heavy cables to tie the packs together.

My quick sketching suggests that even if you have to split a parallel string betwen two packs, it will still work IF you put the half-strings in series with the rest on each side, and run the connecting cables between the half strings so that they are wired in parallel... However this is still not as good as just having one monolithic pack assembly.

ex-Gooserider

[long gone]

I thought they were an oddball size. Meaning replacing wheels with standard inch diameter/width versions.

Re: wanted pneus pour alber adventure

Hello i wand to buy other tires for my alber adventure BLACK size 90/70-10 et 75/70-6 it is possible to put another size on this wheelchair ??? thank you

Are your wheels 10 inch diameter?

If so there are lots of tyres. http://ssl.delti.com/cgi-bin/rshop.pl?d ... htweiter=1 for eg.

[Burgerman]

Well maybe not. I seem to remember that they were an odd size and made specifically. And fragile with a reputation for failure on the rear. I think getting tyres the same overall size may be easy. But they will need different rims?

What size are your tyres/rims?

[long gone]

I do not even have the chair yet trying to do my homework on its weak points ready for some modifications that will improve use and reliability ( etill using a Quikie f55s) . Getting back onto the power subject its good to know Rolls Royce agree with going for the biggest monolithic pile that can be fitted into the box http://www.axeon.com/Customers/Electric-Vehicles.aspx and this is the unit that I am considering for powering the Hyperion http://www.ebay.co.uk/itm/SkyRC-eFuel-1 ... 6645932%26.

[Burgerman]

That company are just guys that (claim) to understand lithium batteries. They use other manufacturers cells, and develop a "SYSTEM" that works for each application by the like of RR or whoever asks them..

RR for eg don't know much about batteries. Or engines. Most of the western worlds car companies, the Japanese bike industry, etc all use a little known company called Recardo in the UK for all serious development work on engines and similar.

The3 power supply, I like. Because its RED! And shiny! Is it any good? Who knows! For a little more you can get a Mastech or Digimess power supply like mine!

[Willywonka1968]

I'm very interested to replace my 2 x 12 v 80 a gel batteries with lithium

[Lord Chatterley]

Ricardo -as in David.

LC

[steves1977uk]

Having got nearly all the parts to convert my chair to lithium, there's one thing I'm not sure about, how are the balance wires arranged on a 8s x 5p or 8s x 6p? Are they spread out evenly across the pack?

Thanks,

Steve

[Burgerman]

http://www.wheelchairdriver.com/convert ... ithium.htm

Basically an 8 cell pack (or multiples of 8) gives you your 24 volts.

It goes:


+cell- +cell- +cell- +cell- +cell- +cell- +cell- +cell-


So you join 9 balance wires. One goes to each end, and the remaining 7 go to all the point in between... So between every + - on that drawing.

See here:
http://scriptasylum.com/rc_speed/lipo.html

Choose say a 4cell (12v) and to show balance wiring...

[flagman1776]

Except that, as we were just discussing, the Hyperion has 2 outlet balance ports... either or both of which can balance up to 7 cells. Since our "24" V pack has 8 cells, the cells must be divided in some manner. (7 & 1) or (6 & 2) or (5 & 3) or (4 & 4)

So if we are going to balance charge Port A: +cell1- +cell2- +cell3- +cell4- Port B: +cell5- +cell6- +cell7- +cell8-
In most cases, you only need a single wire between cells it is the - for one & the + for the next one.
BUT where you split the pack between ports A & B... the simplest way to think about it is to run 2 wires. In my example, one wire will go to Port A, cell4 -, the other balance wire will go to Port B, cell5 +. But they start at the same screw between cells.

[steves1977uk]

Thanks for the explanation BM & flagman.

I was thinking of doing it like this for each row of cells:-

RW +cell- BW +cell- BW +cell- BW +cell- BW +cell- BW +cell- BW +cell- RW/BW +cell- BW

RW= Red Wire BW= Black wire

I'm going to be using a standard 9-pin PC Serial cable connectors for the balance wires and a SB50 Anderson connectors for the power.

Does this look ok?

Steve

[Burgerman]

I think electrons are colour-blind. They don't much care. As long as the wires go to the correct place!

[expresso]

i love the idea of this - but i am very stupid when it comes to doing this myself - so my question is -

is there any battery which is already done - just a drop in replacement -

i got this link from here - this looks just like a direct replacement -


http://www.evassemble.com/index.php?mai ... ucts_id=36

http://www.evassemble.com/index.php?mai ... ucts_id=37


http://www.evassemble.com/index.php?mai ... ucts_id=35

now - my batteries are group 24 - at about 75 Ah -

are these direct replacements ? would just changing to these batteries all thats needed - or is there more involved - it looks as if all the work has been done and these would be just a drop in replacement - sounds too easy - but thats what i am hopping for

[Burgerman]

Its only 60Ah... And a car starter battery.

You can get 108Ah in the same space as a pair of wheelchair batteries, with all the C rate, battery longevity, range advantages that lithium allows. This doesn't really achieve anything over lead.
+

It has no balance system, and relies on well selected / matched cells to stay in balance, combined with shallow discharge and high charge voltage to give a balancing "overcharge" all the time that the "started" engine is running as you drive...
Which is a sure way to get a shorter service life. You will note that there is no cycle life figure as this wont work or balance cells at all.

Its low C rated too, and since its also smaller capacity than you could fit, its actually working the battery very hard. The Winston cells have a recommended 0.5C rate continuous (max 3C) current rating. That's means the 60Ah battery which will fit, is really wanting to see a 30Amp load. Short service life? Who knows, but I would expect it, based on C rate and likely balance failure if used for cyclic operation.

They are not meant for deep cycle use. But car starting duties. So likely will have a short life due to cell imbalance when deep cycled.

There is no plug and play easy good solution. When there is, it will still be better still to do it properly and charge properly and not use a BMS.

[expresso]

ok - i though for a moment - that would do it - its always best to do it yourself - but if it made already - and made the same way as you would do it yourself - dont see any difference -

most cases its not the same way - so i get it in that sense - i was looking over your page of step by step on doing it yourself - pretty cool - but the cost is still too high for my taste - i know its worth it for the long run - if you have to pay out of pocket for your batteries - then yes - its worth it for cost and the rest of the benefits -

when those prices come down to about half that cost - things will pick up and more users may give it a go - i cant spend close to $2000 for all the parts and then the labor etc, - when i can just get new batteries free each year if i wear them out etc, - i understand the rest of the benefits which i would love - last longer - faster maybe - less weight etc, -

did you put up a page which outlines each part needed with links to each part etc, and how to connect - all the wiring ? and then the connections which get connected to the wheelchair wire connecting -

would the joystick work the same - battery indicators etc, ? i remember reading here that it wont be accurate reading on the joystick -

[expresso]

http://www.alibaba.com/product-gs/89683 ... ttery.html


would something like this work - some benefits ?

[ex-Gooserider]

http://www.alibaba.com/product-gs/896831161/12v60ah_lithium_ion_battery.html


would something like this work - some benefits ?

NO.... See all the previous discussions about pre-packaged car battery replacements - which this is just another variant on (and may just be the maker of some of them...)

ex-Gooserider

[expresso]

ok - i dont know why they say its for wheelchairs etc, when it wont work -

maybe one day in about ten years from now - the industry will make it a standard - if it wasnt so expensive - following burgers page to make them isnt that bad - just not cost effective for me -

thanks -

[Burgerman]

http://www.alibaba.com/product-gs/89683 ... ttery.html

Will not work. It has a 30Amp cont rating. Your typical 100Amp wheelchair controller can pull 200 amps for several seconds at a time, and half that on a ramp for eg for maybe 10 seconds...

And again its only a 60Ah battery! Your grp 24 lead ones are 70 to 80Ah. So what would you really gain?

[expresso]

i dont know - i figure it would be some benefits to it - if in fact they were the correct specs for a direct replacement - since they are not - its a NO Go - i did find a site which can make a set of batteries depending on your Group size etc,

but it would cost somewhere around $2500 for each battery in a group 24 direct replacement - if thats even true - i wouldnt know all the details involved like you would - i didnt bother looking into that - just the price alone - isnt worth it for me

the only way this would be worth it for me - is if the prices are reasonable - meaning not much more than the reg. lead batteries wet get today - and also if i had to pay for them myself out of pocket - then it would be wise for me to do like you do and build them correctly even if it costs more up front -

maybe someone would wake up and build them the way you lay it out on your webpage and make it a direct replacement one day -

[Burgerman]

but it would cost somewhere around $2500 for each battery in a group 24 direct replacement - if thats even true - i wouldnt know all the details involved like you would - i didnt bother looking into that - just the price alone - isnt worth it for me

Is only worth he extra cost of lithium if you maximise the lithium advantage. There is NO group 24 plug and play replacement that can do this.

POSSIBLE Lithium advantages

1. LONGEVITY. they WILL give you 10 years plus service life. Thousands of cycles. But only if you treat them correctly. And charge them correctly. If capacity is too low such as these 50 or 60Amp/h group 24 replacements, or/and max continuous C rate is too low or you take large currents from them they will soon die. Discharge them deeply as hey are too small, and again soon die. To get the big cycle life, LOW discharge rate per Ah is essential. And deep discharge should be avoided. BIGGER Ah BATERIES DO THIS AUOMATICALLY. There are no plug and play batteries that will allow a sensible capacity. You CAN get 108Ah (or greater) in place of the 70Ah GRP24 lead batteries, to massive advantage. So you SHOULD always do this. And they are also very subject to early death and cell damage if a typical BMS and dumb charger is used/included internally... So again no plug and play. See here http://www.wheelchairdriver.com/BMS.htm

2. RANGE. 2.5 to 3x the range is possible if you maximise capacity. If you simply fit the same Ah or less you completely miss he point of lithium altogether and here is no advantage, only extra cost.

3. High C rate advantage if capacity and BATTERY C rate is chosen wisely allows a voltage increase with huge efficiency gains possible. A 24v battery misses out on this too...

So again, lithium is entirely possible today, and it works out massively cheaper long term as well as giving huge benefits. IF you understand it. If you don't, you are screwed and at the mercy of all the manufacturers.

You have two choices. Learn, be adventurous and accept a little risk that comes with being at the cutting edge, or be one of the masses that don't have the advantages. ALL the dumb plug and play solutions are designed o sell lithium batteries to the frankly ignorant masses regardless of how crap it is as a solution. Which is why you wont find these in a manufacturers chair.

[Burgerman]

maybe someone would wake up and build them the way you lay it out on your webpage and make it a direct replacement one day -

No because its "cheaper" to fit a simple small capacity monoblock, with bms, and dumb charger and existing 24v electronics, brushed motors and they dont get it...

[Lord Chatterley]

i dont know - i figure it would be some benefits to it - if in fact they were the correct specs for a direct replacement - since they are not - its a NO Go - i did find a site which can make a set of batteries depending on your Group size etc,

but it would cost somewhere around $2500 for each battery in a group 24 direct replacement - if thats even true - i wouldnt know all the details involved like you would - i didnt bother looking into that - just the price alone - isnt worth it for me

the only way this would be worth it for me - is if the prices are reasonable - meaning not much more than the reg. lead batteries wet get today - and also if i had to pay for them myself out of pocket - then it would be wise for me to do like you do and build them correctly even if it costs more up front -

maybe someone would wake up and build them the way you lay it out on your webpage and make it a direct replacement one day -

I reckon there are 2 basic choices - a pair of relatively low capacity Odysseys which you can charge at 40amps or more [ from a twin bank charger or you car hence a fast charge.]

Or, some high capacity lithium package [without a BMS] which you balance-charge with the Hyperion at 20amps.
[20 amps may not be so fast but because it is a BALANCED charge at least you are charging at the optimum rate of 20 amps for most of the time.]

Which choice you take should rest on your usage - I lived in a hilly area and I prefer to travel at 8-9mph so needed high capacity lithiums.

LC